The group named "Unclassified Group" is a system created group. It cannot be edited or deleted.
If you have contacts listed in that group, that means they are not currently a part of any groups in your PastorsLine account.
Once you add a person to a group, we remove them from that unclassified group.
This is just one more way to help you manage your subscribers. Double check this group and see if any action is needed. Maybe they have not finished a data capture or need to be deleted from the database.